| 摘要 |
In a paper-making machine a roll (22) is composed of two parts: a metallic base shell (38), which is constructed of conventional spun-cast steel alloy; and a thin outer shell (40) constructed of a material of high thermal diffusivity. The outer shell (40) is one to a few tenths of an inch thick and is in intimate contact with the surface of the steel alloy base shell (38). Typical materials of high thermal diffusivity for uses in the outer shell (40) are copper and aluminum. The roll (22) may be formed by flame spraying a layer of copper approximately two-tenths of an inch thick on the surface of a steel alloy base shell (38). The roll (22) is employed where improved heat transfer to a paper web is desired for example in an impulse paper dryer, or in a calendar. |
